Optical data recording/reproducing apparatus and optical data storage medium for use in the same

摘要

Disclosed is an optical data apparatus for recording and regenerating data on an optical disc, optical card, or the like. There are particularly disclosed an optical data apparatus and an optical data storage medium appropriate for the apparatus capable of detecting a tracking error signal effective particularly for an optical data storage medium on which optical data are recorded at a high density. A pattern is formed on a track and in a position displaced from the track by half cycle of the track in a first servo pattern area, and no pattern is formed in a second servo pattern area. The first servo pattern area and the second servo pattern area are arranged adjacent to each other. The tracking error signal is obtained through multiplication of differential signals obtained at the timing of Sa1 and Sa2. The tracking error signal can be detected up to a spatial cutoff frequency twice as high as the frequency in the conventional case by means of a conventional optical system.